liblttng-ust/lttng-events.c

   1 /*
   2  * lttng-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _LGPL_SOURCE
  24 #include <stdio.h>
  25 #include <assert.h>
  26 #include <errno.h>
  27 #include <limits.h>
  28 #include <pthread.h>
  29 #include <sys/shm.h>
  30 #include <sys/ipc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <inttypes.h>
  34 #include <time.h>
  35 #include <stdbool.h>
  36 #include <unistd.h>
  37 #include <lttng/ust-endian.h>
  38
  39 #include <urcu-bp.h>
  40 #include <urcu/arch.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/hlist.h>
  43 #include <urcu/list.h>
  44 #include <urcu/uatomic.h>
  45
  46 #include <lttng/tracepoint.h>
  47 #include <lttng/ust-events.h>
  48
  49 #include <usterr-signal-safe.h>
  50 #include <helper.h>
  51 #include <lttng/ust-ctl.h>
  52 #include <ust-comm.h>
  53 #include <ust-fd.h>
  54 #include <lttng/ust-dynamic-type.h>
  55 #include <lttng/ust-context-provider.h>
  56 #include "error.h"
  57 #include "compat.h"
  58 #include "lttng-ust-uuid.h"
  59
  60 #include "tracepoint-internal.h"
  61 #include "string-utils.h"
  62 #include "lttng-bytecode.h"
  63 #include "lttng-tracer.h"
  64 #include "lttng-tracer-core.h"
  65 #include "lttng-ust-statedump.h"
  66 #include "ust-events-internal.h"
  67 #include "wait.h"
  68 #include "../libringbuffer/shm.h"
  69 #include "jhash.h"
  70 #include <lttng/ust-abi.h>
  71
  72 /*
  73  * All operations within this file are called by the communication
  74  * thread, under ust_lock protection.
  75  */
  76
  77 static CDS_LIST_HEAD(sessions);
  78 static CDS_LIST_HEAD(event_notifier_groups);
  79
  80 struct cds_list_head *_lttng_get_sessions(void)
  81 {
  82         return &sessions;
  83 }
  84
  85 static void _lttng_event_destroy(struct lttng_event *event);
  86 static void _lttng_event_notifier_destroy(
  87                 struct lttng_event_notifier *event_notifier);
  88 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  89
  90 static
  91 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  92 static
  93 void lttng_session_sync_event_enablers(struct lttng_session *session);
  94 static
  95 void lttng_event_notifier_group_sync_enablers(
  96                 struct lttng_event_notifier_group *event_notifier_group);
  97 static
  98 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  99
 100 /*
 101  * Called with ust lock held.
 102  */
 103 int lttng_session_active(void)
 104 {
 105         struct lttng_session *iter;
 106
 107         cds_list_for_each_entry(iter, &sessions, node) {
 108                 if (iter->active)
 109                         return 1;
 110         }
 111         return 0;
 112 }
 113
 114 static
 115 int lttng_loglevel_match(int loglevel,
 116                 unsigned int has_loglevel,
 117                 enum lttng_ust_loglevel_type req_type,
 118                 int req_loglevel)
 119 {
 120         if (!has_loglevel)
 121                 loglevel = TRACE_DEFAULT;
 122         switch (req_type) {
 123         case LTTNG_UST_LOGLEVEL_RANGE:
 124                 if (loglevel <= req_loglevel
 125                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 126                         return 1;
 127                 else
 128                         return 0;
 129         case LTTNG_UST_LOGLEVEL_SINGLE:
 130                 if (loglevel == req_loglevel
 131                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 132                         return 1;
 133                 else
 134                         return 0;
 135         case LTTNG_UST_LOGLEVEL_ALL:
 136         default:
 137                 if (loglevel <= TRACE_DEBUG)
 138                         return 1;
 139                 else
 140                         return 0;
 141         }
 142 }
 143
 144 void synchronize_trace(void)
 145 {
 146         synchronize_rcu();
 147 }
 148
 149 struct lttng_session *lttng_session_create(void)
 150 {
 151         struct lttng_session *session;
 152         int i;
 153
 154         session = zmalloc(sizeof(struct lttng_session));
 155         if (!session)
 156                 return NULL;
 157         if (lttng_session_context_init(&session->ctx)) {
 158                 free(session);
 159                 return NULL;
 160         }
 161         CDS_INIT_LIST_HEAD(&session->chan_head);
 162         CDS_INIT_LIST_HEAD(&session->events_head);
 163         CDS_INIT_LIST_HEAD(&session->enums_head);
 164         CDS_INIT_LIST_HEAD(&session->enablers_head);
 165         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 166                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 167         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 168                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 169         cds_list_add(&session->node, &sessions);
 170         return session;
 171 }
 172
 173 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 174 {
 175         struct lttng_event_notifier_group *event_notifier_group;
 176         int i;
 177
 178         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 179         if (!event_notifier_group)
 180                 return NULL;
 181
 182         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 183         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 184         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 185                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 186
 187         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 188
 189         return event_notifier_group;
 190 }
 191
 192 /*
 193  * Only used internally at session destruction.
 194  */
 195 static
 196 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 197 {
 198         struct channel *chan;
 199         struct lttng_ust_shm_handle *handle;
 200
 201         cds_list_del(&lttng_chan->node);
 202         lttng_destroy_context(lttng_chan->ctx);
 203         chan = lttng_chan->chan;
 204         handle = lttng_chan->handle;
 205         /*
 206          * note: lttng_chan is private data contained within handle. It
 207          * will be freed along with the handle.
 208          */
 209         channel_destroy(chan, handle, 0);
 210 }
 211
 212 static
 213 void register_event(struct lttng_event *event)
 214 {
 215         int ret;
 216         const struct lttng_event_desc *desc;
 217
 218         assert(event->registered == 0);
 219         desc = event->desc;
 220         ret = __tracepoint_probe_register_queue_release(desc->name,
 221                         desc->probe_callback,
 222                         event, desc->signature);
 223         WARN_ON_ONCE(ret);
 224         if (!ret)
 225                 event->registered = 1;
 226 }
 227
 228 static
 229 void register_event_notifier(struct lttng_event_notifier *event_notifier)
 230 {
 231         int ret;
 232         const struct lttng_event_desc *desc;
 233
 234         assert(event_notifier->registered == 0);
 235         desc = event_notifier->desc;
 236         ret = __tracepoint_probe_register_queue_release(desc->name,
 237                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 238         WARN_ON_ONCE(ret);
 239         if (!ret)
 240                 event_notifier->registered = 1;
 241 }
 242
 243 static
 244 void unregister_event(struct lttng_event *event)
 245 {
 246         int ret;
 247         const struct lttng_event_desc *desc;
 248
 249         assert(event->registered == 1);
 250         desc = event->desc;
 251         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 252                         desc->probe_callback,
 253                         event);
 254         WARN_ON_ONCE(ret);
 255         if (!ret)
 256                 event->registered = 0;
 257 }
 258
 259 static
 260 void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
 261 {
 262         int ret;
 263         const struct lttng_event_desc *desc;
 264
 265         assert(event_notifier->registered == 1);
 266         desc = event_notifier->desc;
 267         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 268                 desc->u.ext.event_notifier_callback, event_notifier);
 269         WARN_ON_ONCE(ret);
 270         if (!ret)
 271                 event_notifier->registered = 0;
 272 }
 273
 274 /*
 275  * Only used internally at session destruction.
 276  */
 277 static
 278 void _lttng_event_unregister(struct lttng_event *event)
 279 {
 280         if (event->registered)
 281                 unregister_event(event);
 282 }
 283
 284 /*
 285  * Only used internally at session destruction.
 286  */
 287 static
 288 void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 289 {
 290         if (event_notifier->registered)
 291                 unregister_event_notifier(event_notifier);
 292 }
 293
 294 void lttng_session_destroy(struct lttng_session *session)
 295 {
 296         struct lttng_channel *chan, *tmpchan;
 297         struct lttng_event *event, *tmpevent;
 298         struct lttng_enum *_enum, *tmp_enum;
 299         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 300
 301         CMM_ACCESS_ONCE(session->active) = 0;
 302         cds_list_for_each_entry(event, &session->events_head, node) {
 303                 _lttng_event_unregister(event);
 304         }
 305         synchronize_trace();    /* Wait for in-flight events to complete */
 306         __tracepoint_probe_prune_release_queue();
 307         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 308                         &session->enablers_head, node)
 309                 lttng_event_enabler_destroy(event_enabler);
 310         cds_list_for_each_entry_safe(event, tmpevent,
 311                         &session->events_head, node)
 312                 _lttng_event_destroy(event);
 313         cds_list_for_each_entry_safe(_enum, tmp_enum,
 314                         &session->enums_head, node)
 315                 _lttng_enum_destroy(_enum);
 316         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 317                 _lttng_channel_unmap(chan);
 318         cds_list_del(&session->node);
 319         lttng_destroy_context(session->ctx);
 320         free(session);
 321 }
 322
 323 void lttng_event_notifier_group_destroy(
 324                 struct lttng_event_notifier_group *event_notifier_group)
 325 {
 326         int close_ret;
 327         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 328         struct lttng_event_notifier *notifier, *tmpnotifier;
 329
 330         if (!event_notifier_group) {
 331                 return;
 332         }
 333
 334         cds_list_for_each_entry(notifier,
 335                         &event_notifier_group->event_notifiers_head, node)
 336                 _lttng_event_notifier_unregister(notifier);
 337
 338         synchronize_trace();
 339
 340         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 341                         &event_notifier_group->enablers_head, node)
 342                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 343
 344         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 345                         &event_notifier_group->event_notifiers_head, node)
 346                 _lttng_event_notifier_destroy(notifier);
 347
 348         /* Close the notification fd to the listener of event notifiers. */
 349
 350         lttng_ust_lock_fd_tracker();
 351         close_ret = close(event_notifier_group->notification_fd);
 352         if (!close_ret) {
 353                 lttng_ust_delete_fd_from_tracker(
 354                                 event_notifier_group->notification_fd);
 355         } else {
 356                 PERROR("close");
 357                 abort();
 358         }
 359         lttng_ust_unlock_fd_tracker();
 360
 361         cds_list_del(&event_notifier_group->node);
 362
 363         free(event_notifier_group);
 364 }
 365
 366 static
 367 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 368 {
 369         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 370         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 371
 372         if (!enabler) {
 373                 return;
 374         }
 375
 376         /* Destroy filter bytecode */
 377         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 378                         &enabler->filter_bytecode_head, node) {
 379                 free(filter_node);
 380         }
 381
 382         /* Destroy excluders */
 383         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 384                         &enabler->excluder_head, node) {
 385                 free(excluder_node);
 386         }
 387 }
 388
 389  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 390 {
 391         if (!event_notifier_enabler) {
 392                 return;
 393         }
 394
 395         cds_list_del(&event_notifier_enabler->node);
 396
 397         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 398
 399         free(event_notifier_enabler);
 400 }
 401
 402 static
 403 int lttng_enum_create(const struct lttng_enum_desc *desc,
 404                 struct lttng_session *session)
 405 {
 406         const char *enum_name = desc->name;
 407         struct lttng_enum *_enum;
 408         struct cds_hlist_head *head;
 409         int ret = 0;
 410         size_t name_len = strlen(enum_name);
 411         uint32_t hash;
 412         int notify_socket;
 413
 414         /* Check if this enum is already registered for this session. */
 415         hash = jhash(enum_name, name_len, 0);
 416         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 417
 418         _enum = lttng_ust_enum_get_from_desc(session, desc);
 419         if (_enum) {
 420                 ret = -EEXIST;
 421                 goto exist;
 422         }
 423
 424         notify_socket = lttng_get_notify_socket(session->owner);
 425         if (notify_socket < 0) {
 426                 ret = notify_socket;
 427                 goto socket_error;
 428         }
 429
 430         _enum = zmalloc(sizeof(*_enum));
 431         if (!_enum) {
 432                 ret = -ENOMEM;
 433                 goto cache_error;
 434         }
 435         _enum->session = session;
 436         _enum->desc = desc;
 437
 438         ret = ustcomm_register_enum(notify_socket,
 439                 session->objd,
 440                 enum_name,
 441                 desc->nr_entries,
 442                 desc->entries,
 443                 &_enum->id);
 444         if (ret < 0) {
 445                 DBG("Error (%d) registering enumeration to sessiond", ret);
 446                 goto sessiond_register_error;
 447         }
 448         cds_list_add(&_enum->node, &session->enums_head);
 449         cds_hlist_add_head(&_enum->hlist, head);
 450         return 0;
 451
 452 sessiond_register_error:
 453         free(_enum);
 454 cache_error:
 455 socket_error:
 456 exist:
 457         return ret;
 458 }
 459
 460 static
 461 int lttng_create_enum_check(const struct lttng_type *type,
 462                 struct lttng_session *session)
 463 {
 464         switch (type->atype) {
 465         case atype_enum:
 466         {
 467                 const struct lttng_enum_desc *enum_desc;
 468                 int ret;
 469
 470                 enum_desc = type->u.legacy.basic.enumeration.desc;
 471                 ret = lttng_enum_create(enum_desc, session);
 472                 if (ret && ret != -EEXIST) {
 473                         DBG("Unable to create enum error: (%d)", ret);
 474                         return ret;
 475                 }
 476                 break;
 477         }
 478         case atype_enum_nestable:
 479         {
 480                 const struct lttng_enum_desc *enum_desc;
 481                 int ret;
 482
 483                 enum_desc = type->u.enum_nestable.desc;
 484                 ret = lttng_enum_create(enum_desc, session);
 485                 if (ret && ret != -EEXIST) {
 486                         DBG("Unable to create enum error: (%d)", ret);
 487                         return ret;
 488                 }
 489                 break;
 490         }
 491         case atype_dynamic:
 492         {
 493                 const struct lttng_event_field *tag_field_generic;
 494                 const struct lttng_enum_desc *enum_desc;
 495                 int ret;
 496
 497                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 498                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 499                 ret = lttng_enum_create(enum_desc, session);
 500                 if (ret && ret != -EEXIST) {
 501                         DBG("Unable to create enum error: (%d)", ret);
 502                         return ret;
 503                 }
 504                 break;
 505         }
 506         default:
 507                 /* TODO: nested types when they become supported. */
 508                 break;
 509         }
 510         return 0;
 511 }
 512
 513 static
 514 int lttng_create_all_event_enums(size_t nr_fields,
 515                 const struct lttng_event_field *event_fields,
 516                 struct lttng_session *session)
 517 {
 518         size_t i;
 519         int ret;
 520
 521         /* For each field, ensure enum is part of the session. */
 522         for (i = 0; i < nr_fields; i++) {
 523                 const struct lttng_type *type = &event_fields[i].type;
 524
 525                 ret = lttng_create_enum_check(type, session);
 526                 if (ret)
 527                         return ret;
 528         }
 529         return 0;
 530 }
 531
 532 static
 533 int lttng_create_all_ctx_enums(size_t nr_fields,
 534                 const struct lttng_ctx_field *ctx_fields,
 535                 struct lttng_session *session)
 536 {
 537         size_t i;
 538         int ret;
 539
 540         /* For each field, ensure enum is part of the session. */
 541         for (i = 0; i < nr_fields; i++) {
 542                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 543
 544                 ret = lttng_create_enum_check(type, session);
 545                 if (ret)
 546                         return ret;
 547         }
 548         return 0;
 549 }
 550
 551 /*
 552  * Ensure that a state-dump will be performed for this session at the end
 553  * of the current handle_message().
 554  */
 555 int lttng_session_statedump(struct lttng_session *session)
 556 {
 557         session->statedump_pending = 1;
 558         lttng_ust_sockinfo_session_enabled(session->owner);
 559         return 0;
 560 }
 561
 562 int lttng_session_enable(struct lttng_session *session)
 563 {
 564         int ret = 0;
 565         struct lttng_channel *chan;
 566         int notify_socket;
 567
 568         if (session->active) {
 569                 ret = -EBUSY;
 570                 goto end;
 571         }
 572
 573         notify_socket = lttng_get_notify_socket(session->owner);
 574         if (notify_socket < 0)
 575                 return notify_socket;
 576
 577         /* Set transient enabler state to "enabled" */
 578         session->tstate = 1;
 579
 580         /* We need to sync enablers with session before activation. */
 581         lttng_session_sync_event_enablers(session);
 582
 583         /*
 584          * Snapshot the number of events per channel to know the type of header
 585          * we need to use.
 586          */
 587         cds_list_for_each_entry(chan, &session->chan_head, node) {
 588                 const struct lttng_ctx *ctx;
 589                 const struct lttng_ctx_field *fields = NULL;
 590                 size_t nr_fields = 0;
 591                 uint32_t chan_id;
 592
 593                 /* don't change it if session stop/restart */
 594                 if (chan->header_type)
 595                         continue;
 596                 ctx = chan->ctx;
 597                 if (ctx) {
 598                         nr_fields = ctx->nr_fields;
 599                         fields = ctx->fields;
 600                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 601                                 session);
 602                         if (ret < 0) {
 603                                 DBG("Error (%d) adding enum to session", ret);
 604                                 return ret;
 605                         }
 606                 }
 607                 ret = ustcomm_register_channel(notify_socket,
 608                         session,
 609                         session->objd,
 610                         chan->objd,
 611                         nr_fields,
 612                         fields,
 613                         &chan_id,
 614                         &chan->header_type);
 615                 if (ret) {
 616                         DBG("Error (%d) registering channel to sessiond", ret);
 617                         return ret;
 618                 }
 619                 if (chan_id != chan->id) {
 620                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 621                                 chan_id, chan->id);
 622                         return -EINVAL;
 623                 }
 624         }
 625
 626         /* Set atomically the state to "active" */
 627         CMM_ACCESS_ONCE(session->active) = 1;
 628         CMM_ACCESS_ONCE(session->been_active) = 1;
 629
 630         ret = lttng_session_statedump(session);
 631         if (ret)
 632                 return ret;
 633 end:
 634         return ret;
 635 }
 636
 637 int lttng_session_disable(struct lttng_session *session)
 638 {
 639         int ret = 0;
 640
 641         if (!session->active) {
 642                 ret = -EBUSY;
 643                 goto end;
 644         }
 645         /* Set atomically the state to "inactive" */
 646         CMM_ACCESS_ONCE(session->active) = 0;
 647
 648         /* Set transient enabler state to "disabled" */
 649         session->tstate = 0;
 650         lttng_session_sync_event_enablers(session);
 651 end:
 652         return ret;
 653 }
 654
 655 int lttng_channel_enable(struct lttng_channel *channel)
 656 {
 657         int ret = 0;
 658
 659         if (channel->enabled) {
 660                 ret = -EBUSY;
 661                 goto end;
 662         }
 663         /* Set transient enabler state to "enabled" */
 664         channel->tstate = 1;
 665         lttng_session_sync_event_enablers(channel->session);
 666         /* Set atomically the state to "enabled" */
 667         CMM_ACCESS_ONCE(channel->enabled) = 1;
 668 end:
 669         return ret;
 670 }
 671
 672 int lttng_channel_disable(struct lttng_channel *channel)
 673 {
 674         int ret = 0;
 675
 676         if (!channel->enabled) {
 677                 ret = -EBUSY;
 678                 goto end;
 679         }
 680         /* Set atomically the state to "disabled" */
 681         CMM_ACCESS_ONCE(channel->enabled) = 0;
 682         /* Set transient enabler state to "enabled" */
 683         channel->tstate = 0;
 684         lttng_session_sync_event_enablers(channel->session);
 685 end:
 686         return ret;
 687 }
 688
 689 static inline
 690 struct cds_hlist_head *borrow_hash_table_bucket(
 691                 struct cds_hlist_head *hash_table,
 692                 unsigned int hash_table_size,
 693                 const struct lttng_event_desc *desc)
 694 {
 695         const char *event_name;
 696         size_t name_len;
 697         uint32_t hash;
 698
 699         event_name = desc->name;
 700         name_len = strlen(event_name);
 701
 702         hash = jhash(event_name, name_len, 0);
 703         return &hash_table[hash & (hash_table_size - 1)];
 704 }
 705
 706 /*
 707  * Supports event creation while tracing session is active.
 708  */
 709 static
 710 int lttng_event_create(const struct lttng_event_desc *desc,
 711                 struct lttng_channel *chan)
 712 {
 713         struct lttng_event *event;
 714         struct lttng_session *session = chan->session;
 715         struct cds_hlist_head *head;
 716         int ret = 0;
 717         int notify_socket, loglevel;
 718         const char *uri;
 719
 720         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 721                 LTTNG_UST_EVENT_HT_SIZE, desc);
 722
 723         notify_socket = lttng_get_notify_socket(session->owner);
 724         if (notify_socket < 0) {
 725                 ret = notify_socket;
 726                 goto socket_error;
 727         }
 728
 729         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 730                         session);
 731         if (ret < 0) {
 732                 DBG("Error (%d) adding enum to session", ret);
 733                 goto create_enum_error;
 734         }
 735
 736         /*
 737          * Check if loglevel match. Refuse to connect event if not.
 738          */
 739         event = zmalloc(sizeof(struct lttng_event));
 740         if (!event) {
 741                 ret = -ENOMEM;
 742                 goto cache_error;
 743         }
 744         event->chan = chan;
 745
 746         /* Event will be enabled by enabler sync. */
 747         event->enabled = 0;
 748         event->registered = 0;
 749         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 750         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 751         event->desc = desc;
 752
 753         if (desc->loglevel)
 754                 loglevel = *(*event->desc->loglevel);
 755         else
 756                 loglevel = TRACE_DEFAULT;
 757         if (desc->u.ext.model_emf_uri)
 758                 uri = *(desc->u.ext.model_emf_uri);
 759         else
 760                 uri = NULL;
 761
 762         /* Fetch event ID from sessiond */
 763         ret = ustcomm_register_event(notify_socket,
 764                 session,
 765                 session->objd,
 766                 chan->objd,
 767                 desc->name,
 768                 loglevel,
 769                 desc->signature,
 770                 desc->nr_fields,
 771                 desc->fields,
 772                 uri,
 773                 &event->id);
 774         if (ret < 0) {
 775                 DBG("Error (%d) registering event to sessiond", ret);
 776                 goto sessiond_register_error;
 777         }
 778
 779         cds_list_add(&event->node, &chan->session->events_head);
 780         cds_hlist_add_head(&event->hlist, head);
 781         return 0;
 782
 783 sessiond_register_error:
 784         free(event);
 785 cache_error:
 786 create_enum_error:
 787 socket_error:
 788         return ret;
 789 }
 790
 791 static
 792 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 793                 uint64_t token,
 794                 struct lttng_event_notifier_group *event_notifier_group)
 795 {
 796         struct lttng_event_notifier *event_notifier;
 797         struct cds_hlist_head *head;
 798         int ret = 0;
 799
 800         /*
 801          * Get the hashtable bucket the created lttng_event_notifier object
 802          * should be inserted.
 803          */
 804         head = borrow_hash_table_bucket(
 805                 event_notifier_group->event_notifiers_ht.table,
 806                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 807
 808         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 809         if (!event_notifier) {
 810                 ret = -ENOMEM;
 811                 goto error;
 812         }
 813
 814         event_notifier->group = event_notifier_group;
 815         event_notifier->user_token = token;
 816
 817         /* Event notifier will be enabled by enabler sync. */
 818         event_notifier->enabled = 0;
 819         event_notifier->registered = 0;
 820
 821         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 822         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 823         event_notifier->desc = desc;
 824
 825         cds_list_add(&event_notifier->node,
 826                         &event_notifier_group->event_notifiers_head);
 827         cds_hlist_add_head(&event_notifier->hlist, head);
 828
 829         return 0;
 830
 831 error:
 832         return ret;
 833 }
 834
 835 static
 836 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 837 {
 838         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 839
 840         /* Remove from event_notifier list. */
 841         cds_list_del(&event_notifier->node);
 842         /* Remove from event_notifier hash table. */
 843         cds_hlist_del(&event_notifier->hlist);
 844
 845         lttng_free_event_notifier_filter_runtime(event_notifier);
 846
 847         /* Free event_notifier enabler refs */
 848         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 849                         &event_notifier->enablers_ref_head, node)
 850                 free(enabler_ref);
 851         free(event_notifier);
 852 }
 853
 854 static
 855 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 856                 struct lttng_enabler *enabler)
 857 {
 858         int loglevel = 0;
 859         unsigned int has_loglevel = 0;
 860
 861         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 862         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 863                         desc->name, SIZE_MAX))
 864                 return 0;
 865         if (desc->loglevel) {
 866                 loglevel = *(*desc->loglevel);
 867                 has_loglevel = 1;
 868         }
 869         if (!lttng_loglevel_match(loglevel,
 870                         has_loglevel,
 871                         enabler->event_param.loglevel_type,
 872                         enabler->event_param.loglevel))
 873                 return 0;
 874         return 1;
 875 }
 876
 877 static
 878 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 879                 struct lttng_enabler *enabler)
 880 {
 881         int loglevel = 0;
 882         unsigned int has_loglevel = 0;
 883
 884         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 885         if (strcmp(desc->name, enabler->event_param.name))
 886                 return 0;
 887         if (desc->loglevel) {
 888                 loglevel = *(*desc->loglevel);
 889                 has_loglevel = 1;
 890         }
 891         if (!lttng_loglevel_match(loglevel,
 892                         has_loglevel,
 893                         enabler->event_param.loglevel_type,
 894                         enabler->event_param.loglevel))
 895                 return 0;
 896         return 1;
 897 }
 898
 899 static
 900 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 901                 struct lttng_enabler *enabler)
 902 {
 903         switch (enabler->format_type) {
 904         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 905         {
 906                 struct lttng_ust_excluder_node *excluder;
 907
 908                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 909                         return 0;
 910                 }
 911
 912                 /*
 913                  * If the matching event matches with an excluder,
 914                  * return 'does not match'
 915                  */
 916                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 917                         int count;
 918
 919                         for (count = 0; count < excluder->excluder.count; count++) {
 920                                 int len;
 921                                 char *excluder_name;
 922
 923                                 excluder_name = (char *) (excluder->excluder.names)
 924                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 925                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 926                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 927                                         return 0;
 928                         }
 929                 }
 930                 return 1;
 931         }
 932         case LTTNG_ENABLER_FORMAT_EVENT:
 933                 return lttng_desc_match_event_enabler(desc, enabler);
 934         default:
 935                 return -EINVAL;
 936         }
 937 }
 938
 939 static
 940 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 941                 struct lttng_event *event)
 942 {
 943         if (lttng_desc_match_enabler(event->desc,
 944                         lttng_event_enabler_as_enabler(event_enabler))
 945                         && event->chan == event_enabler->chan)
 946                 return 1;
 947         else
 948                 return 0;
 949 }
 950
 951 static
 952 int lttng_event_notifier_enabler_match_event_notifier(
 953                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 954                 struct lttng_event_notifier *event_notifier)
 955 {
 956         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
 957                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 958
 959         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
 960                         event_notifier->user_token == event_notifier_enabler->user_token)
 961                 return 1;
 962         else
 963                 return 0;
 964 }
 965
 966 static
 967 struct lttng_enabler_ref *lttng_enabler_ref(
 968                 struct cds_list_head *enabler_ref_list,
 969                 struct lttng_enabler *enabler)
 970 {
 971         struct lttng_enabler_ref *enabler_ref;
 972
 973         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
 974                 if (enabler_ref->ref == enabler)
 975                         return enabler_ref;
 976         }
 977         return NULL;
 978 }
 979
 980 /*
 981  * Create struct lttng_event if it is missing and present in the list of
 982  * tracepoint probes.
 983  */
 984 static
 985 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 986 {
 987         struct lttng_session *session = event_enabler->chan->session;
 988         struct lttng_probe_desc *probe_desc;
 989         const struct lttng_event_desc *desc;
 990         struct lttng_event *event;
 991         int i;
 992         struct cds_list_head *probe_list;
 993
 994         probe_list = lttng_get_probe_list_head();
 995         /*
 996          * For each probe event, if we find that a probe event matches
 997          * our enabler, create an associated lttng_event if not
 998          * already present.
 999          */
1000         cds_list_for_each_entry(probe_desc, probe_list, head) {
1001                 for (i = 0; i < probe_desc->nr_events; i++) {
1002                         int ret;
1003                         bool found = false;
1004                         struct cds_hlist_head *head;
1005                         struct cds_hlist_node *node;
1006
1007                         desc = probe_desc->event_desc[i];
1008                         if (!lttng_desc_match_enabler(desc,
1009                                         lttng_event_enabler_as_enabler(event_enabler)))
1010                                 continue;
1011
1012                         head = borrow_hash_table_bucket(
1013                                 session->events_ht.table,
1014                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1015
1016                         cds_hlist_for_each_entry(event, node, head, hlist) {
1017                                 if (event->desc == desc
1018                                                 && event->chan == event_enabler->chan) {
1019                                         found = true;
1020                                         break;
1021                                 }
1022                         }
1023                         if (found)
1024                                 continue;
1025
1026                         /*
1027                          * We need to create an event for this
1028                          * event probe.
1029                          */
1030                         ret = lttng_event_create(probe_desc->event_desc[i],
1031                                         event_enabler->chan);
1032                         if (ret) {
1033                                 DBG("Unable to create event %s, error %d\n",
1034                                         probe_desc->event_desc[i]->name, ret);
1035                         }
1036                 }
1037         }
1038 }
1039
1040 static
1041 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1042                 void (*event_func)(struct lttng_session *session,
1043                         struct lttng_event *event),
1044                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1045 {
1046         struct cds_hlist_node *node, *tmp_node;
1047         struct cds_list_head *sessionsp;
1048         unsigned int i;
1049
1050         /* Get handle on list of sessions. */
1051         sessionsp = _lttng_get_sessions();
1052
1053         /*
1054          * Iterate over all events in the probe provider descriptions and
1055          * sessions to queue the unregistration of the events.
1056          */
1057         for (i = 0; i < provider_desc->nr_events; i++) {
1058                 const struct lttng_event_desc *event_desc;
1059                 struct lttng_event_notifier_group *event_notifier_group;
1060                 struct lttng_event_notifier *event_notifier;
1061                 struct lttng_session *session;
1062                 struct cds_hlist_head *head;
1063                 struct lttng_event *event;
1064
1065                 event_desc = provider_desc->event_desc[i];
1066
1067                 /*
1068                  * Iterate over all session to find the current event
1069                  * description.
1070                  */
1071                 cds_list_for_each_entry(session, sessionsp, node) {
1072                         /*
1073                          * Get the list of events in the hashtable bucket and
1074                          * iterate to find the event matching this descriptor.
1075                          */
1076                         head = borrow_hash_table_bucket(
1077                                 session->events_ht.table,
1078                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1079
1080                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1081                                 if (event_desc == event->desc) {
1082                                         event_func(session, event);
1083                                         break;
1084                                 }
1085                         }
1086                 }
1087
1088                 /*
1089                  * Iterate over all event_notifier groups to find the current event
1090                  * description.
1091                  */
1092                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1093                         /*
1094                          * Get the list of event_notifiers in the hashtable bucket and
1095                          * iterate to find the event_notifier matching this
1096                          * descriptor.
1097                          */
1098                         head = borrow_hash_table_bucket(
1099                                 event_notifier_group->event_notifiers_ht.table,
1100                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1101
1102                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1103                                 if (event_desc == event_notifier->desc) {
1104                                         event_notifier_func(event_notifier);
1105                                         break;
1106                                 }
1107                         }
1108                 }
1109         }
1110 }
1111
1112 static
1113 void _unregister_event(struct lttng_session *session,
1114                 struct lttng_event *event)
1115 {
1116         _lttng_event_unregister(event);
1117 }
1118
1119 static
1120 void _event_enum_destroy(struct lttng_session *session,
1121                 struct lttng_event *event)
1122 {
1123         unsigned int i;
1124
1125         /* Destroy enums of the current event. */
1126         for (i = 0; i < event->desc->nr_fields; i++) {
1127                 const struct lttng_enum_desc *enum_desc;
1128                 const struct lttng_event_field *field;
1129                 struct lttng_enum *curr_enum;
1130
1131                 field = &(event->desc->fields[i]);
1132                 switch (field->type.atype) {
1133                 case atype_enum:
1134                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1135                         break;
1136                 case atype_enum_nestable:
1137                         enum_desc = field->type.u.enum_nestable.desc;
1138                         break;
1139                 default:
1140                         continue;
1141                 }
1142
1143                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1144                 if (curr_enum) {
1145                         _lttng_enum_destroy(curr_enum);
1146                 }
1147         }
1148
1149         /* Destroy event. */
1150         _lttng_event_destroy(event);
1151 }
1152
1153 /*
1154  * Iterate over all the UST sessions to unregister and destroy all probes from
1155  * the probe provider descriptor received as argument. Must me called with the
1156  * ust_lock held.
1157  */
1158 void lttng_probe_provider_unregister_events(
1159                 struct lttng_probe_desc *provider_desc)
1160 {
1161         /*
1162          * Iterate over all events in the probe provider descriptions and sessions
1163          * to queue the unregistration of the events.
1164          */
1165         probe_provider_event_for_each(provider_desc, _unregister_event,
1166                 _lttng_event_notifier_unregister);
1167
1168         /* Wait for grace period. */
1169         synchronize_trace();
1170         /* Prune the unregistration queue. */
1171         __tracepoint_probe_prune_release_queue();
1172
1173         /*
1174          * It is now safe to destroy the events and remove them from the event list
1175          * and hashtables.
1176          */
1177         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1178                 _lttng_event_notifier_destroy);
1179 }
1180
1181 /*
1182  * Create events associated with an event enabler (if not already present),
1183  * and add backward reference from the event to the enabler.
1184  */
1185 static
1186 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1187 {
1188         struct lttng_session *session = event_enabler->chan->session;
1189         struct lttng_event *event;
1190
1191         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1192                 goto end;
1193
1194         /* First ensure that probe events are created for this enabler. */
1195         lttng_create_event_if_missing(event_enabler);
1196
1197         /* For each event matching enabler in session event list. */
1198         cds_list_for_each_entry(event, &session->events_head, node) {
1199                 struct lttng_enabler_ref *enabler_ref;
1200
1201                 if (!lttng_event_enabler_match_event(event_enabler, event))
1202                         continue;
1203
1204                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1205                         lttng_event_enabler_as_enabler(event_enabler));
1206                 if (!enabler_ref) {
1207                         /*
1208                          * If no backward ref, create it.
1209                          * Add backward ref from event to enabler.
1210                          */
1211                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1212                         if (!enabler_ref)
1213                                 return -ENOMEM;
1214                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1215                                 event_enabler);
1216                         cds_list_add(&enabler_ref->node,
1217                                 &event->enablers_ref_head);
1218                 }
1219
1220                 /*
1221                  * Link filter bytecodes if not linked yet.
1222                  */
1223                 lttng_enabler_link_bytecode(event->desc,
1224                         &session->ctx,
1225                         &event->filter_bytecode_runtime_head,
1226                         lttng_event_enabler_as_enabler(event_enabler));
1227
1228                 /* TODO: merge event context. */
1229         }
1230 end:
1231         return 0;
1232 }
1233
1234 /*
1235  * Called at library load: connect the probe on all enablers matching
1236  * this event.
1237  * Called with session mutex held.
1238  */
1239 int lttng_fix_pending_events(void)
1240 {
1241         struct lttng_session *session;
1242
1243         cds_list_for_each_entry(session, &sessions, node) {
1244                 lttng_session_lazy_sync_event_enablers(session);
1245         }
1246         return 0;
1247 }
1248
1249 int lttng_fix_pending_event_notifiers(void)
1250 {
1251         struct lttng_event_notifier_group *event_notifier_group;
1252
1253         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1254                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1255         }
1256         return 0;
1257 }
1258
1259 /*
1260  * For each session of the owner thread, execute pending statedump.
1261  * Only dump state for the sessions owned by the caller thread, because
1262  * we don't keep ust_lock across the entire iteration.
1263  */
1264 void lttng_handle_pending_statedump(void *owner)
1265 {
1266         struct lttng_session *session;
1267
1268         /* Execute state dump */
1269         do_lttng_ust_statedump(owner);
1270
1271         /* Clear pending state dump */
1272         if (ust_lock()) {
1273                 goto end;
1274         }
1275         cds_list_for_each_entry(session, &sessions, node) {
1276                 if (session->owner != owner)
1277                         continue;
1278                 if (!session->statedump_pending)
1279                         continue;
1280                 session->statedump_pending = 0;
1281         }
1282 end:
1283         ust_unlock();
1284         return;
1285 }
1286
1287 /*
1288  * Only used internally at session destruction.
1289  */
1290 static
1291 void _lttng_event_destroy(struct lttng_event *event)
1292 {
1293         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1294
1295         /* Remove from event list. */
1296         cds_list_del(&event->node);
1297         /* Remove from event hash table. */
1298         cds_hlist_del(&event->hlist);
1299
1300         lttng_destroy_context(event->ctx);
1301         lttng_free_event_filter_runtime(event);
1302         /* Free event enabler refs */
1303         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1304                         &event->enablers_ref_head, node)
1305                 free(enabler_ref);
1306         free(event);
1307 }
1308
1309 static
1310 void _lttng_enum_destroy(struct lttng_enum *_enum)
1311 {
1312         cds_list_del(&_enum->node);
1313         cds_hlist_del(&_enum->hlist);
1314         free(_enum);
1315 }
1316
1317 void lttng_ust_events_exit(void)
1318 {
1319         struct lttng_session *session, *tmpsession;
1320
1321         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1322                 lttng_session_destroy(session);
1323 }
1324
1325 /*
1326  * Enabler management.
1327  */
1328 struct lttng_event_enabler *lttng_event_enabler_create(
1329                 enum lttng_enabler_format_type format_type,
1330                 struct lttng_ust_event *event_param,
1331                 struct lttng_channel *chan)
1332 {
1333         struct lttng_event_enabler *event_enabler;
1334
1335         event_enabler = zmalloc(sizeof(*event_enabler));
1336         if (!event_enabler)
1337                 return NULL;
1338         event_enabler->base.format_type = format_type;
1339         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1340         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1341         memcpy(&event_enabler->base.event_param, event_param,
1342                 sizeof(event_enabler->base.event_param));
1343         event_enabler->chan = chan;
1344         /* ctx left NULL */
1345         event_enabler->base.enabled = 0;
1346         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1347         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1348
1349         return event_enabler;
1350 }
1351
1352 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1353                 struct lttng_event_notifier_group *event_notifier_group,
1354                 enum lttng_enabler_format_type format_type,
1355                 struct lttng_ust_event_notifier *event_notifier_param)
1356 {
1357         struct lttng_event_notifier_enabler *event_notifier_enabler;
1358
1359         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1360         if (!event_notifier_enabler)
1361                 return NULL;
1362         event_notifier_enabler->base.format_type = format_type;
1363         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1364         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1365
1366         event_notifier_enabler->user_token = event_notifier_param->event.token;
1367
1368         memcpy(&event_notifier_enabler->base.event_param.name,
1369                 event_notifier_param->event.name,
1370                 sizeof(event_notifier_enabler->base.event_param.name));
1371         event_notifier_enabler->base.event_param.instrumentation =
1372                 event_notifier_param->event.instrumentation;
1373         event_notifier_enabler->base.event_param.loglevel =
1374                 event_notifier_param->event.loglevel;
1375         event_notifier_enabler->base.event_param.loglevel_type =
1376                 event_notifier_param->event.loglevel_type;
1377
1378         event_notifier_enabler->base.enabled = 0;
1379         event_notifier_enabler->group = event_notifier_group;
1380
1381         cds_list_add(&event_notifier_enabler->node,
1382                         &event_notifier_group->enablers_head);
1383
1384         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1385
1386         return event_notifier_enabler;
1387 }
1388
1389 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1390 {
1391         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1392         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1393
1394         return 0;
1395 }
1396
1397 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1398 {
1399         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1400         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1401
1402         return 0;
1403 }
1404
1405 static
1406 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1407                 struct lttng_ust_bytecode_node *bytecode)
1408 {
1409         bytecode->enabler = enabler;
1410         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1411 }
1412
1413 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1414                 struct lttng_ust_bytecode_node *bytecode)
1415 {
1416         _lttng_enabler_attach_filter_bytecode(
1417                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1418
1419         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1420         return 0;
1421 }
1422
1423 static
1424 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1425                 struct lttng_ust_excluder_node *excluder)
1426 {
1427         excluder->enabler = enabler;
1428         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1429 }
1430
1431 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1432                 struct lttng_ust_excluder_node *excluder)
1433 {
1434         _lttng_enabler_attach_exclusion(
1435                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1436
1437         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1438         return 0;
1439 }
1440
1441 int lttng_event_notifier_enabler_enable(
1442                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1443 {
1444         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1445         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1446
1447         return 0;
1448 }
1449
1450 int lttng_event_notifier_enabler_disable(
1451                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1452 {
1453         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1454         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1455
1456         return 0;
1457 }
1458
1459 int lttng_event_notifier_enabler_attach_filter_bytecode(
1460                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1461                 struct lttng_ust_bytecode_node *bytecode)
1462 {
1463         _lttng_enabler_attach_filter_bytecode(
1464                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1465                 bytecode);
1466
1467         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1468         return 0;
1469 }
1470
1471 int lttng_event_notifier_enabler_attach_exclusion(
1472                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1473                 struct lttng_ust_excluder_node *excluder)
1474 {
1475         _lttng_enabler_attach_exclusion(
1476                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1477                 excluder);
1478
1479         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1480         return 0;
1481 }
1482
1483 int lttng_attach_context(struct lttng_ust_context *context_param,
1484                 union ust_args *uargs,
1485                 struct lttng_ctx **ctx, struct lttng_session *session)
1486 {
1487         /*
1488          * We cannot attach a context after trace has been started for a
1489          * session because the metadata does not allow expressing this
1490          * information outside of the original channel scope.
1491          */
1492         if (session->been_active)
1493                 return -EPERM;
1494
1495         switch (context_param->ctx) {
1496         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1497                 return lttng_add_pthread_id_to_ctx(ctx);
1498         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1499         {
1500                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1501
1502                 perf_ctx_param = &context_param->u.perf_counter;
1503                 return lttng_add_perf_counter_to_ctx(
1504                         perf_ctx_param->type,
1505                         perf_ctx_param->config,
1506                         perf_ctx_param->name,
1507                         ctx);
1508         }
1509         case LTTNG_UST_CONTEXT_VTID:
1510                 return lttng_add_vtid_to_ctx(ctx);
1511         case LTTNG_UST_CONTEXT_VPID:
1512                 return lttng_add_vpid_to_ctx(ctx);
1513         case LTTNG_UST_CONTEXT_PROCNAME:
1514                 return lttng_add_procname_to_ctx(ctx);
1515         case LTTNG_UST_CONTEXT_IP:
1516                 return lttng_add_ip_to_ctx(ctx);
1517         case LTTNG_UST_CONTEXT_CPU_ID:
1518                 return lttng_add_cpu_id_to_ctx(ctx);
1519         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1520                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1521                         ctx);
1522         case LTTNG_UST_CONTEXT_CGROUP_NS:
1523                 return lttng_add_cgroup_ns_to_ctx(ctx);
1524         case LTTNG_UST_CONTEXT_IPC_NS:
1525                 return lttng_add_ipc_ns_to_ctx(ctx);
1526         case LTTNG_UST_CONTEXT_MNT_NS:
1527                 return lttng_add_mnt_ns_to_ctx(ctx);
1528         case LTTNG_UST_CONTEXT_NET_NS:
1529                 return lttng_add_net_ns_to_ctx(ctx);
1530         case LTTNG_UST_CONTEXT_PID_NS:
1531                 return lttng_add_pid_ns_to_ctx(ctx);
1532         case LTTNG_UST_CONTEXT_TIME_NS:
1533                 return lttng_add_time_ns_to_ctx(ctx);
1534         case LTTNG_UST_CONTEXT_USER_NS:
1535                 return lttng_add_user_ns_to_ctx(ctx);
1536         case LTTNG_UST_CONTEXT_UTS_NS:
1537                 return lttng_add_uts_ns_to_ctx(ctx);
1538         case LTTNG_UST_CONTEXT_VUID:
1539                 return lttng_add_vuid_to_ctx(ctx);
1540         case LTTNG_UST_CONTEXT_VEUID:
1541                 return lttng_add_veuid_to_ctx(ctx);
1542         case LTTNG_UST_CONTEXT_VSUID:
1543                 return lttng_add_vsuid_to_ctx(ctx);
1544         case LTTNG_UST_CONTEXT_VGID:
1545                 return lttng_add_vgid_to_ctx(ctx);
1546         case LTTNG_UST_CONTEXT_VEGID:
1547                 return lttng_add_vegid_to_ctx(ctx);
1548         case LTTNG_UST_CONTEXT_VSGID:
1549                 return lttng_add_vsgid_to_ctx(ctx);
1550         default:
1551                 return -EINVAL;
1552         }
1553 }
1554
1555 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1556                 struct lttng_ust_context *context_param)
1557 {
1558         return -ENOSYS;
1559 }
1560
1561 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1562 {
1563         if (!event_enabler) {
1564                 return;
1565         }
1566         cds_list_del(&event_enabler->node);
1567
1568         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1569
1570         lttng_destroy_context(event_enabler->ctx);
1571         free(event_enabler);
1572 }
1573
1574 /*
1575  * lttng_session_sync_event_enablers should be called just before starting a
1576  * session.
1577  */
1578 static
1579 void lttng_session_sync_event_enablers(struct lttng_session *session)
1580 {
1581         struct lttng_event_enabler *event_enabler;
1582         struct lttng_event *event;
1583
1584         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1585                 lttng_event_enabler_ref_events(event_enabler);
1586         /*
1587          * For each event, if at least one of its enablers is enabled,
1588          * and its channel and session transient states are enabled, we
1589          * enable the event, else we disable it.
1590          */
1591         cds_list_for_each_entry(event, &session->events_head, node) {
1592                 struct lttng_enabler_ref *enabler_ref;
1593                 struct lttng_bytecode_runtime *runtime;
1594                 int enabled = 0, has_enablers_without_bytecode = 0;
1595
1596                 /* Enable events */
1597                 cds_list_for_each_entry(enabler_ref,
1598                                 &event->enablers_ref_head, node) {
1599                         if (enabler_ref->ref->enabled) {
1600                                 enabled = 1;
1601                                 break;
1602                         }
1603                 }
1604                 /*
1605                  * Enabled state is based on union of enablers, with
1606                  * intesection of session and channel transient enable
1607                  * states.
1608                  */
1609                 enabled = enabled && session->tstate && event->chan->tstate;
1610
1611                 CMM_STORE_SHARED(event->enabled, enabled);
1612                 /*
1613                  * Sync tracepoint registration with event enabled
1614                  * state.
1615                  */
1616                 if (enabled) {
1617                         if (!event->registered)
1618                                 register_event(event);
1619                 } else {
1620                         if (event->registered)
1621                                 unregister_event(event);
1622                 }
1623
1624                 /* Check if has enablers without bytecode enabled */
1625                 cds_list_for_each_entry(enabler_ref,
1626                                 &event->enablers_ref_head, node) {
1627                         if (enabler_ref->ref->enabled
1628                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1629                                 has_enablers_without_bytecode = 1;
1630                                 break;
1631                         }
1632                 }
1633                 event->has_enablers_without_bytecode =
1634                         has_enablers_without_bytecode;
1635
1636                 /* Enable filters */
1637                 cds_list_for_each_entry(runtime,
1638                                 &event->filter_bytecode_runtime_head, node) {
1639                         lttng_bytecode_filter_sync_state(runtime);
1640                 }
1641         }
1642         __tracepoint_probe_prune_release_queue();
1643 }
1644
1645 static
1646 void lttng_create_event_notifier_if_missing(
1647                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1648 {
1649         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1650         struct lttng_probe_desc *probe_desc;
1651         struct cds_list_head *probe_list;
1652         int i;
1653
1654         probe_list = lttng_get_probe_list_head();
1655
1656         cds_list_for_each_entry(probe_desc, probe_list, head) {
1657                 for (i = 0; i < probe_desc->nr_events; i++) {
1658                         int ret;
1659                         bool found = false;
1660                         const struct lttng_event_desc *desc;
1661                         struct lttng_event_notifier *event_notifier;
1662                         struct cds_hlist_head *head;
1663                         struct cds_hlist_node *node;
1664
1665                         desc = probe_desc->event_desc[i];
1666                         if (!lttng_desc_match_enabler(desc,
1667                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1668                                 continue;
1669
1670                         /*
1671                          * Given the current event_notifier group, get the bucket that
1672                          * the target event_notifier would be if it was already
1673                          * created.
1674                          */
1675                         head = borrow_hash_table_bucket(
1676                                 event_notifier_group->event_notifiers_ht.table,
1677                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1678
1679                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1680                                 /*
1681                                  * Check if event_notifier already exists by checking
1682                                  * if the event_notifier and enabler share the same
1683                                  * description and id.
1684                                  */
1685                                 if (event_notifier->desc == desc &&
1686                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1687                                         found = true;
1688                                         break;
1689                                 }
1690                         }
1691
1692                         if (found)
1693                                 continue;
1694
1695                         /*
1696                          * We need to create a event_notifier for this event probe.
1697                          */
1698                         ret = lttng_event_notifier_create(desc,
1699                                 event_notifier_enabler->user_token,
1700                                 event_notifier_group);
1701                         if (ret) {
1702                                 DBG("Unable to create event_notifier %s, error %d\n",
1703                                         probe_desc->event_desc[i]->name, ret);
1704                         }
1705                 }
1706         }
1707 }
1708
1709 /*
1710  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1711  */
1712 static
1713 int lttng_event_notifier_enabler_ref_event_notifiers(
1714                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1715 {
1716         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1717         struct lttng_event_notifier *event_notifier;
1718
1719          /*
1720           * Only try to create event_notifiers for enablers that are enabled, the user
1721           * might still be attaching filter or exclusion to the
1722           * event_notifier_enabler.
1723           */
1724         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1725                 goto end;
1726
1727         /* First, ensure that probe event_notifiers are created for this enabler. */
1728         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1729
1730         /* Link the created event_notifier with its associated enabler. */
1731         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1732                 struct lttng_enabler_ref *enabler_ref;
1733
1734                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1735                         continue;
1736
1737                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1738                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1739                 if (!enabler_ref) {
1740                         /*
1741                          * If no backward ref, create it.
1742                          * Add backward ref from event_notifier to enabler.
1743                          */
1744                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1745                         if (!enabler_ref)
1746                                 return -ENOMEM;
1747
1748                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1749                                 event_notifier_enabler);
1750                         cds_list_add(&enabler_ref->node,
1751                                 &event_notifier->enablers_ref_head);
1752                 }
1753
1754                 /*
1755                  * Link filter bytecodes if not linked yet.
1756                  */
1757                 lttng_enabler_link_bytecode(event_notifier->desc,
1758                         &event_notifier_group->ctx, &event_notifier->filter_bytecode_runtime_head,
1759                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1760         }
1761 end:
1762         return 0;
1763 }
1764
1765 static
1766 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1767 {
1768         struct lttng_event_notifier_enabler *event_notifier_enabler;
1769         struct lttng_event_notifier *event_notifier;
1770
1771         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1772                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1773
1774         /*
1775          * For each event_notifier, if at least one of its enablers is enabled,
1776          * we enable the event_notifier, else we disable it.
1777          */
1778         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1779                 struct lttng_enabler_ref *enabler_ref;
1780                 struct lttng_bytecode_runtime *runtime;
1781                 int enabled = 0, has_enablers_without_bytecode = 0;
1782
1783                 /* Enable event_notifiers */
1784                 cds_list_for_each_entry(enabler_ref,
1785                                 &event_notifier->enablers_ref_head, node) {
1786                         if (enabler_ref->ref->enabled) {
1787                                 enabled = 1;
1788                                 break;
1789                         }
1790                 }
1791
1792                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1793                 /*
1794                  * Sync tracepoint registration with event_notifier enabled
1795                  * state.
1796                  */
1797                 if (enabled) {
1798                         if (!event_notifier->registered)
1799                                 register_event_notifier(event_notifier);
1800                 } else {
1801                         if (event_notifier->registered)
1802                                 unregister_event_notifier(event_notifier);
1803                 }
1804
1805                 /* Check if has enablers without bytecode enabled */
1806                 cds_list_for_each_entry(enabler_ref,
1807                                 &event_notifier->enablers_ref_head, node) {
1808                         if (enabler_ref->ref->enabled
1809                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1810                                 has_enablers_without_bytecode = 1;
1811                                 break;
1812                         }
1813                 }
1814                 event_notifier->has_enablers_without_bytecode =
1815                         has_enablers_without_bytecode;
1816
1817                 /* Enable filters */
1818                 cds_list_for_each_entry(runtime,
1819                                 &event_notifier->filter_bytecode_runtime_head, node) {
1820                         lttng_bytecode_filter_sync_state(runtime);
1821                 }
1822         }
1823         __tracepoint_probe_prune_release_queue();
1824 }
1825
1826 /*
1827  * Apply enablers to session events, adding events to session if need
1828  * be. It is required after each modification applied to an active
1829  * session, and right before session "start".
1830  * "lazy" sync means we only sync if required.
1831  */
1832 static
1833 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1834 {
1835         /* We can skip if session is not active */
1836         if (!session->active)
1837                 return;
1838         lttng_session_sync_event_enablers(session);
1839 }
1840
1841 /*
1842  * Update all sessions with the given app context.
1843  * Called with ust lock held.
1844  * This is invoked when an application context gets loaded/unloaded. It
1845  * ensures the context callbacks are in sync with the application
1846  * context (either app context callbacks, or dummy callbacks).
1847  */
1848 void lttng_ust_context_set_session_provider(const char *name,
1849                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1850                 void (*record)(struct lttng_ctx_field *field,
1851                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1852                         struct lttng_channel *chan),
1853                 void (*get_value)(struct lttng_ctx_field *field,
1854                         struct lttng_ctx_value *value))
1855 {
1856         struct lttng_session *session;
1857
1858         cds_list_for_each_entry(session, &sessions, node) {
1859                 struct lttng_channel *chan;
1860                 struct lttng_event *event;
1861                 int ret;
1862
1863                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1864                                 name, get_size, record, get_value);
1865                 if (ret)
1866                         abort();
1867                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1868                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1869                                         name, get_size, record, get_value);
1870                         if (ret)
1871                                 abort();
1872                 }
1873                 cds_list_for_each_entry(event, &session->events_head, node) {
1874                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1875                                         name, get_size, record, get_value);
1876                         if (ret)
1877                                 abort();
1878                 }
1879         }
1880 }
1881
1882 /*
1883  * Update all event_notifier groups with the given app context.
1884  * Called with ust lock held.
1885  * This is invoked when an application context gets loaded/unloaded. It
1886  * ensures the context callbacks are in sync with the application
1887  * context (either app context callbacks, or dummy callbacks).
1888  */
1889 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1890                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1891                 void (*record)(struct lttng_ctx_field *field,
1892                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1893                         struct lttng_channel *chan),
1894                 void (*get_value)(struct lttng_ctx_field *field,
1895                         struct lttng_ctx_value *value))
1896 {
1897         struct lttng_event_notifier_group *event_notifier_group;
1898
1899         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1900                 int ret;
1901
1902                 ret = lttng_ust_context_set_provider_rcu(
1903                                 &event_notifier_group->ctx,
1904                                 name, get_size, record, get_value);
1905                 if (ret)
1906                         abort();
1907         }
1908 }